# Ubuntu – Ubuntu 12.04 w/unity – Mouse lag

12.04mouse scrollunity

Dell Latitude-E6500
3.2.0-24-generic #37-Ubuntu SMP x86_64 x86_64 GNU/Linux
Driver – 295.40

Here is my problem.
My mouse lags in Ubuntu. It is always a few ms "late", and often not completely on target either. It is system-wide, not only when scrolling on web pages. The HW I am using is the same I used when running Kubuntu 11.10, which performed light years better compared to Unity – and, with no mouse lag what so ever. I am aware of the bug with the current Nvidia driver (295.40), but it is the same with the Noveau driver as well. It has nothing to do with setting the acceleration and sensitivity levels. It is the actual input that seems weird.

It is the same on a single laptop monitor and on my dual monitor setup.

Can it be kernel thing? Did they change how mousepolling is done? Any compiz tweaks available?

I plan to test this with Kubuntu 12.04 to see if it happens with KWIN too.

Thanks.

I've run into this before, and this fixed it for me. However, I've just changed this back to the original state, and it doesn't seem to be re-appearing. Perhaps it has been made moot by an upgrade -- but here's the process I used to fix it.

If you are running into the problem now, and just want to test real quick if this fix works, you can do the temporary:

sudo sh -c 'echo N > /sys/module/drm_kms_helper/parameters/poll'


To keep this change, do:

sudo sh -c 'echo "options drm_kms_helper poll=0" >> /etc/modprobe.d/local.conf'
sudo update-initramfs -u